NZ Photo Info

In 6 easy steps...

There are times when it is desirable to remove the background from images. This tutorial will take you through the process step-by-step using the freely available gimp software. This tutorial assumes you are running the Windows version, but the concept applies equally to other versions of the gimp and other photo editing software such as Photoshop.

The assumption is that you have a basic understanding of how to use the gimp.

There are many ways to achieve this - the method that we will describe here uses the quick mask tool - a fairly quick and precise method that can be mastered easily.

I have selected a simple image with a well defined transition between the image and the background to demonstrate the technique.

This is process is best done on the full size image - don't resize prior to removing the background otherwise you will need to be much more precise and most likely end up with a jagged looking picture.

Step 1

Using the lasso tool make a rough selection around the image that you want to remove the background from.

Step 2

Activate the quick mask tool by selecting the little square at the bottom left side of the main image window. Once selected your image should look something similar to this:

Step 3

Using the pencil tool you will need to shade the background more precisely around your image.

• This step is best done with the image zoomed at around 200%.
• Start with a large pencil size around 15 pixels to take you closer to the edges.
• finish off with a pencil size of 3 pixels to define the edge of your image.
• This is the most important part of the process and will require attention to detail.
• Using a black pencil will result in adding to the masked area or background.
• If you make a mistake don't worry. You can either use "Ctrl Z" to undo your last action or change the pencil to white which will result in removing the mask.

You should have a nicely outlines copy of your image with the background masked.

Step 4

Toggle the quick mask off and copy the image and paste as new. This will result in a copy of your image without the background.

Step 5

You are almost finished. The image just needs a little bit of cleaning up.

Add alpha to the selection - this can be done from the layers tool ("Ctrl l") by right clicking on the layer:

• Now you want to shrink the selection by 1 or 2 pixels.
• Invert the selection.
• Feather the selection by 1 or 2 pixels
• "Ctrl + k" to clear
• "Ctrl + Shift + A" to unselect.
• Save your image.

Step 6

Congratulations you have finished!